Valtrex

What Is Valtrex (Valacyclovir)?

Valtrex is the brand name for valacyclovir, an antiviral drug used to treat infections caused by certain types of viruses.

In adults, it’s prescribed for shingles (herpes zoster), cold sores around the mouth, and to help lessen the effects of genital herpes.

In children, it’s used to treat cold sores (in kids over 12) and chicken pox (in children over age 2).

Valtrex is not a cure for herpes, but it can help reduce your symptoms by slowing the growth and spread of the virus.

This gives the body’s immune system a better chance to fight off the infection and reduce the number of outbreaks.

The drug can decrease herpes pain and itching, help sores heal, and prevent new sores from forming.

This medication is also prescribed off-label to treat cytomegalovirus, another type of viral infection that’s a concern for pregnant women and people with weakened immune systems, especially after an organ transplant.

The Food and Drug Administration approved Valtrex in 1995.

In 2012, the maker of Valtrex, Glaxo Smith Kline, agreed to pay $3 billion dollars to settle federal charges of fraud that included allegations that the company paid healthcare professionals kickbacks to prescribe some drugs including Valtrex.

At the time, this was the largest healthcare fraud settlement in U.S. history.

Valtrex Warnings

The side effects of Valtrex may be more severe in older adults, especially kidney problems and mental/mood changes (such as confusion and agitation).

Valtrex does not prevent the spread of herpes, so take precautions to protect a sex partner. Don’t have sexual contact during an outbreak or if you have symptoms.

Be aware herpes can be passed on even when you are symptom-free, so always use effective barrier methods like condoms and dental dams.

Cold sores are also spread easily, so avoid kissing or other close contact with people until your sores have completely healed.

Even touching a cold sore with your finger, then touching someone else, can pass the virus, so wash hands frequently when you have an outbreak.

Tell your doctor if you’ve been diagnosed with HIV/AIDS, or if you have a weak immune system.

Valtrex can be harmful to the kidneys. The risk increases when you take it with other medications that can harm the kidneys.

Make sure to let your physician know about any drugs you’re already taking, any history of kidney disease, dialysis treatment, or if you’ve had a kidney or bone marrow transplant.

Talk to your doctor before having certain immunizations like vaccinations against the varicella virus.

Pregnancy and Valtrex

Valtrex is not expected to harm an unborn child but discuss a pregnancy with your doctor.

Herpes can be passed from an infected mother to a baby if the mother has a genital lesion during childbirth.

Valtrex will pass into breast milk and could harm a nursing infant.

Do not take this drug without talking to your doctor if you plan to breastfeed.

Valtrex Interactions

Since Valtrex is a type of antiviral medication, it can inactivate a varicella or zoster vaccine before your body can develop immunity to the virus, essentially voiding the benefits of the immunization.

Your doctor may delay giving these vaccines until Valtrex is out of your system.

Drugs that cause kidney problems, like a non-steroidal anti-inflammatory drug (NSAID) like ibuprofen or naproxen, can interact with Valtrex.

Since Valtrex is very similar to acyclovir (Zovirax), you should not take the two medications at the same time.

Probenecid (Benemid) and cimetidine (Tagamet) are two drugs that may reduce you kidney’s ability to clear Valtrex out of the body, leading to high concentrations of Valtrex in the blood and possible side effects.

This medication can make you dizzy. It’s best to avoid drinking alcohol since the combination could increase the effect.

You should always tell your healthcare professional about all prescription, non-prescription, over-the-counter, illegal and recreational drugs, herbal remedies, nutritional and dietary supplements, and any other drugs and treatments.

Valtrex Dosage

This medication works best if you take it at the very first sign on an outbreak. Delaying treatment can lessen the effectiveness of Valtrex.

For shingles or chickenpox, take the drug as soon as a rash appears. For cold sores or genital herpes, take the medication at the first sign of an outbreak or when you feel burning, tingling, or itching.

Valtrex works best when the mediation is at constant levels in your system, so take it at evenly spaced intervals as prescribed by your doctor.

The frequency and intervals of your dose depend on what you’re taking it for.

For shingles: every eight hours (three times a day), for seven days

For genital herpes: twice a day for five to 10 days

These are general guidelines; follow the directions on your prescription label carefully.

Continue to take Valtrex until the full prescription amount is finished. Do not alter the dose or stop the medication without talking to your doctor.

Do not give this medication to a child without a prescription.

Valtrex Overdose

Seek emergency medical attention or call a poison help line at (800) 222-1222 in case of an overdose of Valtrex.

Overdose symptoms may include:

Changes in the amount of your urine

Extreme tiredness

Mental/mood changes

A loss of consciousness or seizures

Missed Dose of Valtrex

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose.

Valtrex FAQ

Q: I am currently taking Valtrex for my varicella-zoster virus and my insurance company suggests I ask my doctor if there is a cheaper medication that I may be able to take. Would you know the names of those particular medications?

A: Varicella zoster, or shingles, is usually treated with either Valtrex (valacyclovir) or Famvir (famciclovir). The brand name versions of these medications are expensive but they both come in generic forms that should help with your insurance copays. The insurance company most likely wants the physician to use acyclovir, which is not generally used for shingles, because it is not as effective against the virus.
Lori Mendoza, PharmD

Q: What are the side effects of Valtrex?

A: There are a very few possible side effects to this medication, however we, as pharmacists, rarely discuss the potential problems that people may have because it increases the possibility that people will have a reaction. For example, I could give a 10 patients sugar pills, and tell them that it may cause some gastrointestinal discomfort. Typically, 9 out of 10 of those patients will be running to the restroom within an hour. My personal feeling is that Valtrex and Zovirax should be put on over-the-counter status. If you are really concerned with some of the side effects after you begin treatment, by all means, contact a health care provider and ask questions; however, I would like to emphasize that the benefits of this medication far outweigh the shortcomings and I would hate to find someone not increase their quality of life because of what 'might' happen. If you would like more information, please visit us here: http://www.everydayhealth.com/drugs/valtrex Matt Curley, PharmD

Q: Is there anything, other than Valtrex, that can be taken for herpes suppression treatment? I seldom have outbreaks and they are so mild that it's not a problem for me. I am going to start a sexual relationship and was told this is what I should do to help protect my partner. It is so expensive and makes me tired and I'm not happy about taking it. Is there something else I could take?

A: There are three prescription drugs available for the management of genital herpes - Valtrex (valacyclovir), Zovirax (acyclovir), and Famvir (famciclovir), but only Valtrex has been proven to reduce the transmission of genital herpes. According to the package insert, Valtrex is generally well tolerated when used to reduce transmission of genital herpes. The most common side effects of Valtrex are headache, nausea, and cold symptoms. Less frequently, decreases in red and/or white blood cell counts have occurred in patients taking Valtrex. Fatigue can be a symptom of decreased blood counts. Please check with your health care provider. With regard to medication costs, these antiviral drugs are available in generic form, which are less expensive. Check with your local pharmacist. During a herpes outbreak, patients can help prevent transmission of the virus to other people by keeping the sores clean and dry, avoiding contact with sores, washing their hands after any contact with sores, and avoiding sexual activity until sores have completely healed. For more information about genital herpes: http://www.everydayhealth.com/sexual-health/STDs/what-are-genital-herpes.aspx. Michelle McDermott, PharmD

Q: If I have genital herpes and a white sore on my tongue, will Valtrex help it, or do I need to change to something else?

A: Valtrex (valacyclovir) is an antiviral drug used to slow the growth and spread of the herpes virus. Valtrex is used to treat infections caused by herpes viruses which include gential herpes, cold sores, shingles, and chickenpox. I cannot diagnosis the white sore in your mouth on your tongue. If it is not related to any of the listed medical condition, Valtrex will not help. Contact your primary care physician to have the spot diagnosed. Take your current prescription of Valtrex only as prescribed. Do not start or stop any medications or treatments without first talking to your doctor. You can also find helpful information on Valtrex at http://www.everydayhealth.com/drugs/valtrex.
Jennifer Carey, PharmD

Q: What is the difference between Tricor versus generic Zocor?

A: There are many differences between Tricor (fenofibrate) versus generic Zocor (simvastatin) for the treatment of high cholesterol. A main difference between Tricor versus generic Zocor, known as simvastatin, is that these medications belong to different treatment categories and their pharmacologic action targets different components of the lipid profile.
Tricor belong to a group of medications known as fibrates, while simvastatin belongs to a group of medications commonly referred to as the statins. Treatment with Tricor is indicated primarly to decrease triglyceride levels and increase high-density lipoprotein (HDL or "good c holesterol") levels. Fibrates, such as Tricor, are typically the treatment option of choice in patients with high cholesterol and elevated triglyceride levels. Treatment with generic Zocor, simvastatin, is indicated primarily to decrease low-density (LDL or "bad cholesterol") levels and to reduce the risk of coronary heart disease and cardiovascular events, such as heart attack, stroke and death. In addition, simvastatin can also lower triglyceride levels and slightly raise HDL levels. However, statins, such as simvastatin, are typically the treatment option of choice in patients with elevated LDL levels and those at high risk of coronary heart disease.
Another difference between Tricor versus generic Zocor is approved use in the pediatric population. While simvastatin is currently approved by the U.S. Food and Drug Adminstration (FDA) for the treatment of heterozygous familial hypercholesterolemia in adolescents aged 10 to 17 years, the safety and effectiveness of Tricor in the pediatric population has not been established.
Another difference between Tricor versus generic Zocor is there is currently no generic equivalent available for Tricor.
Another significant difference between Tricor versus generic Zocor is FDA pregnancy category. Tricor is considered pregnancy category C, while simvastatin is considered pregnancy category X and contraindicated in women who are or may become pregnant. Although Tricor is not absolutely contraindicated in pregnancy as simvastatin is, it should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
There are many differences between Tricor (fenofibrate) versus generic Zocor (simvastatin) for the treatment of high cholesterol. A main difference between Tricor versus generic Zocor, known as simvastatin, is that these medications belong to different treatment categories and their pharmacologic action targets different components of the lipid profile.
Tricor belong to a group of medications known as fibrates, while simvastatin belongs to a group of medications commonly referred to as the statins. Treatment with Tricor is indicated primarly to decrease triglyceride levels and increase high-density lipoprotein (HDL or "good c holesterol") levels. Fibrates, such as Tricor, are typically the treatment option of choice in patients with high cholesterol and elevated triglyceride levels. Treatment with generic Zocor, simvastatin, is indicated primarily to decrease low-density (LDL or "bad cholesterol") levels and to reduce the risk of coronary heart disease and cardiovascular events, such as heart attack, stroke and death. In addition, simvastatin can also lower triglyceride levels and slightly raise HDL levels. However, statins, such as simvastatin, are typically the treatment option of choice in patients with elevated LDL levels and those at high risk of coronary heart disease.
Another difference between Tricor versus generic Zocor is approved use in the pediatric population. While simvastatin is currently approved by the U.S. Food and Drug Adminstration (FDA) for the treatment of heterozygous familial hypercholesterolemia in adolescents aged 10 to 17 years, the safety and effectiveness of Tricor in the pediatric population has not been established.
Another difference between Tricor versus generic Zocor is there is currently no generic equivalent available for Tricor.
Another significant difference between Tricor versus generic Zocor is FDA pregnancy category. Tricor is considered pregnancy category C, while simvastatin is considered pregnancy category X and contraindicated in women who are or may become pregnant. Although Tricor is not absolutely contraindicated in pregnancy as simvastatin is, it should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

Q: Can I use Valtrex for shingles?

A: Valtrex (valacyclovir) is approved for shingles, also referred to as herpes zoster, in immunocompetent adults. However, the effectiveness of Valtrex for shingles when treatment is initiated more than 72 hours after the onset of rash has not been established. The safety and effectiveness of Valtrex for the treatment of patients with disseminated herpes zoster (disseminated shingles) has not been established. In addition, the safety and effectiveness of Valtrex for shingles in patients younger than 18 years of age has also not been established.
Valtrex is an antiviral medication. To use Valtrex for shingles, the usual recommended adult dosage is 1 gram administered three times daily for 7 days of treatment. Patients are advised to initiate therapy as soon as possible after a diagnosis of shingles. Therapy should be initiated at the earliest sign or symptom of shingles, such as tingling, burning and blisters, and is most effective when initiated within 48 hours of the onset of rash. There is no data available on treatment initiated after 72 hours following the onset of rash. Valtrex may be administered without regard to meals.
To use Valtrex for shingles, patients should also be advised to maintain adequate hydration during treatment.
During clinical trials of Valtrex for shingles treatment, the adverse reactions reported by patients included nausea, headache, vomiting, dizziness and abdominal pain.
Shingles is caused by the same herpes virus that causes chickenpox. Shingles can occur in individuals who have previously had chickenpox. The virus that causes shingles can be spread to individuals who have not had chickenpox previously or the chickenpox vaccination and is spread though contact with the affected areas of the skin. It is unknown if Valtrex can stop the spread of shingles to other individuals.
To take Valtrex for shingles, patients should be advised to take their medication exactly as prescribed by a health care provider.

Q: Can I use Valtrex for genital herpes?

A: Valtrex (valacyclovir) is used for genital herpes treatment in immunocompetent patients for the initial episode or for recurrent episodes. For the initial episode, the effectiveness of Valtrex for genital herpes when treatment is initiated more than 72 hours following the onset of signs and symptoms has not been established. For recurrent episodes, the effectiveness of Valtrex for genital herpes has not been established when treatment is initiated more than 24 hours following the onset of signs and symptoms.
Valtrex is used for genital herpes as chronic suppressive therapy of recurrent episodes in immunocompetent and in HIV-infected patients. The safety and effectiveness of Valtrex for suppressive therapy has not been established beyond one year in immunocompetent patients and beyond six months in HIV-infected patients.
Valtrex is also used for genital herpes for the reduction of transmission of the virus in immunocompetent adults. In addition to treatment with Valtrex for suppressive therapy, patients are advised to engage in safer sex practices as outlined by the Centers for Disease Control and Prevention's (CDC) Sexually Transmitted Diseases Treatment Guidelines. The effectiveness of Valtrex for the reduction of transmission of genital herpes has not been established past 8 months in couples in which one partner has genital herpes and the other partner does not. In addition, the effectiveness of Valtrex for the reduction of virus transmission has not been established in patients with multiple partners or non-heterosexual partners.
Valtrex is an antiviral medication. To use Valtrex for genital herpes, patients should be advised to take their medication exactly as prescribed by a health care provider.
To use Valtrex for genital herpes, dosage and administration depends upon the reason for use. To use Valtrex for an initial episode of genital herpes, the recommended dosage is 1 gram administered twice daily for 10 days of treatment. Research has demonstrated that treatment with Valtrex is most effective when initiated within 48 hours of the onset of signs and symptoms. For recurrent episodes of genital herpes, the usual dosage of Valtrex is 500 mg administered twice daily for 3 days. Patients are advised to initiate treatment at the first sign or symptom of an episode, according to the prescribing information.
Lastly, to use Valtrex for chronic suppressive therapy of recurrent genital herpes, the recommended dosage is 1 gram administered once daily in immunocompetent patients. In the population of patients who experience 9 recurrences or less per year, 500 mg administered once daily may be considered as an alternative dose. In patients infected with HIV, with a CD4+ cell count greater than or equal to 100, the usual recommended dosage is 500 mg administered twice daily. Valtrex may be administered without regard to meals.

Q: What is Valtrex?

A: Valtrex (valacyclovir) is an antiviral medication indicated for the treatment of cold sores and shingles caused by herpes viruses, for the treatment and control of genital herpes in adults with healthy immune systems, to control genital herpes infections in HIV-infected patients and, in conjunction with safer sex practices, for the reduction of transmission of genital herpes. The safety and efficacy of Valtrex in HIV-infected patients has not been established for any treatment other than the suppression of genital herpes. Valtex is also indicated for the treatment of chickenpox in pediatric patients ages 2 to 17 with healthy immune systems and for the treatment of cold sores in pediatric patients 12 years of age and older. Valtrex cannot cure herpes infections. However, it is beneficial in reducing the symptoms associated with the infection.
During clinical trials of Valtrex, the most commonly observed adverse reactions, reported for at least one indication by more than 10% of adult patients being treated, included headache, nausea and abdominal pain. The only adverse reaction observed in more than 10% of pediatric patients less than 18 years of age was headache.
The dosage and administration of Valtrex depends upon the age of the patient, immune system status and indication for use. Valtrex can be administered without regard to meals. Valtrex is currently available in caplet form and can be extemporaneously compounded into a suspension for patients unable to swallow the caplets. Treatment with Valtrex, for cold sores, shingles or genital herpes, should be initiated as soon as possible after the first appearance of symptoms, such as tingling, burning or blisters. Valtrex may not be effective if treatment is initiated too late. Patients being treated with Valtrex are advised to stay adequately hydrated.
More serious adverse reactions are possible with Valtrex treatment and may include thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), acute renal failure and certain central nervous system reactions, including agitation, hallucinations, confusion and encephalopathy. Certain patients are at higher risk for these serious adverse reactions. It is essential for patients to inform their health care provider of any other medical conditions and medications they currently take prior to initiation of treatment with Valtrex and to report any unusual or bothersome symptoms as soon as possible.
Valtrex should be taken exactly as prescribed by a health care provider.

Q: What are the side effects of Valtrex?

A: The most common side effects of Valtrex (valacyclovir), reported during clinical trials, for at least one indication, by more than 10% of adult patients being treated included headache, nausea and abdominal pain. The most common side effect of Valtrex, reported by more than 10% of pediatric patients less than 18 years of age was headache.
In clinical studies for the treatment of cold sores, the reported side effects of Valtrex included headache and dizziness.
In a clinical study for the treatment of an initial episode of genital herpes, the reported side effects of Valtrex included headache and nausea. In several clinical studies for the treatment of recurrent genital herpes, the reported side effects of Valtrex, reported by greater than or equal to 5% of patients, included headache and nausea.
For the suppression of recurrent genital herpes infections in adults with healthy immune systems, the reported side effects of Valtrex included headache, nausea, abdominal pain, dysmenorrhea, depression, arthralgia, vomiting and dizziness. For suppression therapy in HIV-infected patients, reported side effects included headache, fatigue and rash.
Lastly, in a clinical study for the reduction of transmission of genital herpes, the reported side effects included headache, nasopharyngitis and upper respiratory tract infection.
In the pediatric population, studies of patients 12 to 17 years of age, for the treatment of cold sores, revealed side effects including headache and nausea. Clinical studies of pediatric patients under 12 years of age, the reported side effects included diarrhea, pyrexia, dehydration, herpes simplex and rhinorrhea. No clinically significant changes in laboratory values were observed in the pediatric population.
Results of clinical trials also revealed an incidence of laboratory abnormalities in those patients with herpes zoster and genital herpes. Laboratory abnormalities included changes in hemoglobin levels, white blood cell counts, platelet counts, AST and ALT levels (liver enzymes) and serum creatinine.
More serious side effects of Valtrex are possible with treatment and may include thrombotic thrombocytopenic purpura/hemolytic uremic syndrome (TTP/HUS), which can be life-threatening, acute renal failure and certain central nervous system side effects, including agitation, hallucinations, confusion, delirium, seizures and encephalopathy. Certain patients are at higher risk for these serious adverse reactions, including those with certain underlying medical conditions the elderly. It is essential for patients to inform their health care provider of all other medical conditions and any medications they currently take prior to initiation of treatment with Valtrex. Patients are also advised to report any unusual or bothersome symptoms they experience, to their health care provider, as soon as possible.

Q: Can I use Valtrex for oral herpes?

A: Valtrex (valacyclovir) is used for oral herpes, also referred to as cold sores or herpes labialis, in adults and pediatric patients 12 years of age and older.
Valtrex is an antiviral medication. To use Valtrex for oral herpes in adults and pediatric patients 12 years of age and older, the usual recommended dosage is 2 grams administered twice daily for 1 day, with doses being administered 12 hours apart. Treatment should be initiated at the earliest onset of a symptom of a cold sore, such as tingling, itching or burning. The effectiveness of Valtrex for oral herpes has not been established for treatment initiated after the development of the clinical signs of a cold sore, such as a papule, vesicle or ulcer. Valtrex may be administered without regard to meals. Patients should be advised to maintain adequate hydration during treatment with Valtrex.
During clinical trials of Valtrex for oral herpes treatment in adults, the adverse reactions reported by patients included headache and dizziness. During clinical trials of Valtrex for oral herpes in pediatric patients, aged 12 to 17 years, reported adverse reactions included headache and nausea.
Oral herpes, or cold sores, are caused by a herpes virus which may be spread through kissing or other physical contact with the affected area. Cold sores develop in or around the mouth and manifest as small, painful ulcers. It is unknown if Valtrex can stop the spread of oral herpes to other individuals.
To take Valtrex for oral herpes, patients should be advised to take their medication exactly as prescribed by a health care provider. When using Valtrex for oral herpes, it is essential for patients to initiate treatment as soon as possible after they notice symptoms of an outbreak. Valtrex may not be beneficial if treatment is initiated too late.

Q: What are the effects of Valtrex?

A: The pharmacologic effects of Valtrex (valacyclovir) vary depending on the indication for use. Valtrex is an antiviral medication indicated for the treatment and control of infections caused by herpes viruses in adults and children, including genital herpes, cold sores, shingles and chickenpox. The pharmacologic effects of Valtrex for all indications appear to be a result of the inhibition of viral replication.
During clinical trials for shingles (herpes zoster), in adults with healthy immune systems, the effects of Valtrex appeared to shorten the time to cessation of new lesions by 1 day as compared to placebo in patients younger than 50 years of age. All patients were treated with Valtrex within 72 hours of the onset of rash.
Two placebo-controlled clinical trials were conducted to evaluate the effects of Valtrex in adult and adolescent patients, 12 years of age and older, with a history of recurrent cold sores. The results of these studies demonstrated the effects of Valtrex, administered for one day, shortened the average duration of a cold sore episode by approximately one day. The majority of patients in these studies initiated treatment within 2 hours of the onset of symptoms.
During clinical trials for the initial episode of genital herpes infections, in adults with healthy immune systems, the effects of Valtrex included a median time to lesion healing of 9 days, a median time to cessation of pain was 5 days and a median time to cessation of viral shedding was 3 days in patients treated for 10 days. Patients were administered Valtrex within 72 hours of the onset of symptoms.
For adult patients, with healthy immune systems, with recurrent episodes of genital herpes, the effects of Valtrex demonstrated in clinical trials indicated a shortened median time to lesion healing and cessation of viral shedding by 2 days and a shortened median time to cessation of pain by 1 day.
While the effects of Valtrex differ slightly depending on indication for treatment, overall, the effects of Valtrex to inhibit viral replication appears to shorten the duration of the infection.

Q: Is Valtrex safe during Pregnancy?

A: Valtrex (valacyclovir) is an antiviral medication classified by the U.S. Food and Drug Administration (FDA) as Pregnancy Category B.
Studies of Valtrex performed in animals, at doses which precipitated 10 and 7 times the human plasma levels in rats and rabbits respectively, during the formation and differentiation of organs and organ systems during embryonic development, revealed no evidence of teratogenicity. However, there are no adequate and well-controlled studies evaluating Valtrex in pregnant women.
According to Briggs' Drugs in Pregnancy and Lactation, for the management of herpes in pregnancy, Valtrex is recommended for primary or first-episode infection (for 7 to 10 days), symptomatic recurrent episode (for 5 days), and daily suppression (from 36 weeks' gestation until delivery). Experience with Valtrex in early pregnancy is limited. The Briggs' Fetal Risk Recommendation indicates that previous experience with Valtrex in human pregnancy, either for the drug itself or drugs in the same class or with similar mechanisms of action, is adequate to demonstrate that the risk to the embryo/fetus is very low or nonexistent.
According to the prescribing information, Valtrex should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus. The use of Valtrex during pregnancy is patients specific and must be properly evaluated by a health care provider.

Q: What is the difference between Famvir versus Valtrex?

A: The main differences between Famvir (famciclovir) versus Valtrex (valacyclovir) include indications for use approved by the U.S. Food and Drug Administration (FDA), use in the pediatric population and dosage and administration.
The main difference between Famvir versus Valtrex is indication for use. Famvir is indicated for the treatment of herpes labialis (cold sores) and genital herpes, the treatment and suppression of recurrent episodes of genital herpes and herpes zoster (shingles) in adults with healthy immune systems. Famvir is also indicated for the treatment of recurrent episodes of orolabial or genital herpes in HIV-infected adult patients. The difference between Famvir versus Valtrex is Valtrex is indicated for an initial episode and recurrent episodes of genital herpes as well as for reduction of transmission of the virus, while Famvir is only indicated for recurrent episodes and not for the reduction of transmission of the virus. Famvir is indicated for the treatment of recurrent episodes of orolabial or genital herpes in HIV-infected patients, while the safety and efficacy of Valtrex has not been established in HIV-infected patients other than for the suppression of genital herpes. One additional difference between Famvir versus Valtrex, with regard to indications for use, is the time frame for initiation of effective treatment for recurrent episodes of genital herpes in immunocompetent adults. The efficacy of Famvir when initiated more than 6 hours following the onset of symptoms or lesions has not been established. However, the efficacy of treatment with Valtrex when initiated more than 24 hours following the onset of symptoms has not been established. Therefore, research indicates that treatment with Valtrex can be initiated later and still demonstrate effectiveness.
Another difference between Famvir versus Valtrex is approved use in the pediatric population. The safety and efficacy of Famvir has not been established in patients less than 18 years of age, while Valtrex is approved for the treatment of cold sores in pediatric patients 12 years of age and older and for the treatment of chickenpox in children aged 2 to 17 years.
Both Famvir and Valtrex can be taken without regard to food. With regard to dosage, the difference between Famvir versus Valtrex is for treatment of cold sores, Famvir is administered as a single dose, while Valtrex requires administration of two doses 12 hour apart. For the treatment of recurrent episodes of genital herpes, Famvir is administered twice daily for 1 day, while Valtrex must be taken for 3 days. In addition, for suppressive therapy in adults with health immune systems, Famvir must be administered twice daily, while Valtrex only has to be taken once daily. For the treatment of shingles, both Famvir and Valtrex are administered three times daily for 7 days.

Q: Does Valtrex have any side effects that I should be concerned about over the long-term? I'm currently taking it for a first-time outbreak of herpes and don't know yet if I will have to take it daily or not.

A: Valtrex (valacyclovir) is a medication that is used to treat cold sores, shingles, chickenpox and genital herpes. All of these conditions are caused by the herpes virus and Valtrex works by helping the body fight the infection by preventing the virus from replicating. Valtrex also works to prevent outbreaks from recurring. According to the prescribing information on Valtrex, the most common side effects of the medication are: headaches, nausea, abdominal pain, depression, vomiting, joint pain, dizziness, and increased liver enzymes. The prescribing information does not have information on the safety of this medication past one year of therapy. The clinical studies that were conducted did not go longer than one year. If you have any type of immune system suppression or kidney conditions you should tell your physician because a change in dosage is necessary in these situations. Lori Poulin, PharmD

Q: What are the long-term side effects of Valtrex?

A: Valtrex (Valacyclovir) is an antiviral drug that slows down the spread of the herpes virus. Valtrex will not cure the herpes virus but Valtrex will lessen the symptoms of the infection. Valtrex is used for the herpes virus which includes genital herpes, cold sores, chicken pox and shingles. Valtrex can be taken with or without food. Treatment with Valtrex should be started as soon as the first appearance of symptoms. Valtrex is more effective if taken within 1-2 days after the symptoms start. Take Valtrex with a full glass of water. Water is very important when taking Valtrex so the kidneys keep working effectively. Common side effects of Valtrex include nausea, stomach pain, headache, dizziness, and possibly a mild skin rash. Valtrex may cause dizziness which may be made worse if used with alcohol or certain medicines. Talk to your doctor if your experience serious side effects such as increased thirst, loss of appetite, swelling, weight gain, shortness of breath, feeling shaky, or problems with speech or vision. Kimberly Hotz, PharmD

Q: How long can you take Valtrex daily as a supressant for genital herpes? How many years is it safe to do so?

A: According to the prescribing information for Valtrex (valacyclovir), the safety and efficacy of suppressive therapy for genital herpes for longer than one year has not been established. Please consult with your health care provider regarding the optimal duration of treatment that best meets your needs. For more specific information, consult with your doctor or pharmacist for guidance based on your health status and current medications, particularly before taking any action. Kristen Dore, PharmD

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